MONOMERIC SURFACTANTS FOR SURFACE MODIFICATION OF POLYMERS

The surfaces of poly(methyl methacrylate) and a UV-curable acrylic lacquer have been modified by the addition of small amounts of polymerizable, monomeric surfactants and a surface-active polymer. In the system used, the surfactants concentrate at interfaces toward less polar phases. Addition of 1% w/w of a monomeric surfactant to an acrylic lacquer gives a surface concentration of 50% at the interface toward air. The rate of surface enrichment is primarily dependent on the size of the surfactant molecules and on the viscosity of the bulk material to which it is added. Comparison shows that the surfactant-modified surface layers are thicker than monolayers made by the Langmuir-Blodgett technique. The behavior of monomeric surfactants in the outmost surface layer of a modified film is, however, similar to that of a monolayer formed in a Langmuir-Blodgett balance. Contact angle hysteresis measurements show that the surface-active monomers concentrating in the surface of a modified lacquer film become more and more closely packed when the total surfactant concentration is increased. © 1990, American Chemical Society. All rights reserved.